The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
As is known per se, an aircraft engine, which generally consists of a turbojet engine, is placed inside a nacelle which, amongst other functions:
ensures the aerodynamic fairing of the engine,
allows channeling outside air towards the engine, and
allows connecting the engine to the aircraft.
Indeed, the nacelle presents generally a tubular structure comprising an air inlet upstream of the turbojet engine, a median section intended to surround a fan of the turbojet engine, a downstream section intended to surround the combustion chamber of the turbojet engine and accommodating, where appropriate, thrust reversal means.
Modern nacelles are intended to accommodate a bypass turbojet engine capable of generating via the blades of the rotating fan a hot air flow (also called primary flow) originating from the combustion chamber of the turbojet engine and a cold air flow (secondary flow) which circulates outside the turbojet engine through an annular passage, also called secondary flow path, formed between a fairing of the turbojet engine and an inner wall of the nacelle.
The two air flows are ejected from the turbojet engine by the rear of the nacelle.
The role of a thrust reverser, during the landing of an aircraft, is to improve the braking capacity of the latter by redirecting forward at least part of the air ejected from the turbojet engine. In this phase, the thrust reverser obstructs at least part of the flow path of the cold air and directs this flow to the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels and air brakes of the aircraft.
In general, the structure of a thrust reverser comprises a cowl which is mounted movable in longitudinal translation from front backwards according to a direction substantially parallel to the axis of the nacelle, between a closed position in which the cowl ensures the aerodynamic continuity of the nacelle, and an open position in which the cowl opens a passage in the nacelle.
In the case of a cascade-type thrust reverser, the reorientation of the air flow is performed by cascade vanes, associated to thrust reverser flaps brought to block at least partially the air circulation flow path, the cowl having only a simple slide function aiming at uncovering or covering again these cascade vanes.
In turn, the thrust reverser flaps, also called blocking flaps, are activated and driven by sliding of the movable cowl until obstructing at least partially the flow path downstream of the cascades, so as to optimize the reorientation of the cold air flow.
There are known nacelles called “C-Duct,” or “D-Duct,” which comprise a structure called thrust reverser fixed structure which is intended to surround a downstream portion of the turbojet engine.
This fixed structure includes two half-cowls which are deployed “in a butterfly fashion” and which are pivotally hinged by hinges, about a longitudinal hinge axis, between a working position in which the half-cowls form a portion of the downstream fairing of the turbojet engine and define the cold air annular flow path with a thrust reverser cowl, and a maintenance position in which the half-cowls are brought away from the turbojet engine.
Each of the two half-cowls is mounted on a longitudinal support half-beam, called 12 O'clock beam, pivotally mounted on the mast, the rotational movement of each half-beam on the mast ensuring pivoting of each half-cowl relative to this mast.
It is known to equip the nacelle with a fireproof sealing device, such as the device described and represented in the document FR-A1-2920215, which includes a lip sealing gasket designed to be interposed between a cowl of a rear section of a nacelle and a turbojet engine.
There is also known a fireproof sealing device described and represented in the document EP-A2-0835805 which describes and represents a labyrinth gasket including a pair of plates formed between the support mast of the nacelle and an outer structure of the nacelle.
It is known to equip the nacelle with a fireproof sealing device which includes a sealing gasket adapted to provide sealing between a median section of the nacelle which surrounds the fan of the turbojet engine and the 12 O'clock beam area.
To this end, each half-cowl includes a partition wall which extends in a plane perpendicular to the hinge axis and which partitions the 12 O'clock beam area.
The partition wall delimits a seal bearing edge which is arranged opposite the mast.
The sealing device generally includes a tubular gasket made of elastomer which is mounted on the seal bearing edge of the partition wall so as to cooperate with the mast.
When the half-cowls occupy their working position, the associated gasket is compressed by an associated seal bearing wall delimited by the mast.
In particular, the tubular gasket has an intermediate segment which extends in a plane perpendicular to the axis of the nacelle, from a lower portion to an upper portion.
According to the prior art, the upper portion of the tubular gasket bears on a lower face of the hatch for access to the hinges of the associated half-cowl, in order to ensure fireproof sealing.
Nonetheless, on a thrust reverser type, the position of the pivot axis of the half-cowl of the thrust reverser relative to the mast may prevent such a configuration.
Indeed, depending on the transverse and vertical position of the pivot axis of the half-cowl, and the offset of this axis relative to the tubular gasket, the tubular gasket may resist the opening and the closure of the half-cowl by being overcompressed against the mast during pivoting of the half-cowl.